here's another picture from back in the day, aerial during the 1st day FBI search
in time, this is before the newspaper photo I posted, because you can see only some sand is search-disturbed, but the search demarking lines are there.
If you assume there should be disturbed sand around where the money was found, then it seems like the point Tom Kaye identified as the money find site, is up too far from where they are searching.
you can see they are only halfway done on the marks towards the top of the photo (this is looking downstream)
but there is a small area disturbed in the center of the picture, like in the newspaper photo.
added the newspaper photo again for easy comparison.